Working Principle and Characteristics of Butterfly Valves

1. Working Principle

A butterfly valve is a type of valve that opens and closes by rotating a disc plate. Within the cylindrical channel of the butterfly body, the disc rotates around an axis, primarily rotating the plate by 90 degrees. When the flow control disc reaches 90 degrees, the valve is fully open, and the medium flow can be adjusted by changing the valve angle. It is typically installed in the diameter direction of the pipeline. The butterfly valve and valve stem do not have locking functions. To effectively control flow, a worm gear reducer is required. A butterfly valve with a worm gear reducer not only automatically locks the butterfly valve but also alters its operational performance, enabling more precise adjustment of the medium flow.

2. Characteristics

(1) Simple structure and compact design. The structure is compact, with a short length, small volume, and light weight, making it suitable for large diameters.

(2) Low fluid resistance. When fully open, the valve channel has a large effective flow area, resulting in low fluid resistance.

(3) Easy and quick opening/closing with good performance adjustment, rotating 90 degrees. It can be opened or closed. By changing the rotation angle of the disc, the flow rate can be controlled in stages.

(4) The butterfly plates on both sides of the rotating shaft are essentially the same as the medium, generating torque in the same direction, resulting in minimal opening and closing torque. Consequently, opening and closing are easier.

(5) Excellent low-pressure sealing performance. The sealing surface materials are typically made of rubber and plastic, ensuring good sealing performance. However, butterfly valves are limited by the sealing ring materials, resulting in lower operating pressure and temperature ranges. However, the operating pressure and temperature ranges of hard-seal butterfly valves have been significantly improved.